Abstract: A check valve structure includes: a valve casing communicating with each of inflow and outflow paths for a fluid; and a valve element which is disposed in the valve casing and configured of an elastic material. The valve element has a thin portion, and a thick portion protruding from the substantial center of one surface of the thin portion. The valve casing has: a valve element support portion including an annular bottom portion capable of supporting an outer edge of a bottom portion of the thick portion, and a peripheral wall portion continuing to an outer peripheral edge of the annular bottom portion; and a valve seat portion including a valve element contact portion which is in contact with a vicinity of an outer peripheral edge portion on the other surface side of the thin portion, and a valve seat surface which can be in contact with the thin portion.

Abstract: A check valve structure includes: a valve casing communicating with each of inflow and outflow paths for a fluid; and a valve element which is disposed in the valve casing and configured of an elastic material. The valve element has a thin portion, and a thick portion protruding from the substantial center of one surface of the thin portion. The valve casing has: a valve element support portion including an annular bottom portion capable of supporting an outer edge of a bottom portion of the thick portion, and a peripheral wall portion continuing to an outer peripheral edge of the annular bottom portion; and a valve seat portion including a valve element contact portion which is in contact with a vicinity of an outer peripheral edge portion on the other surface side of the thin portion, and a valve seat surface which can be in contact with the thin portion.

Abstract: The vehicle brake-specific diaphragm of the invention includes a vessel-form member and a flange portion formed at a peripheral edge of an opening in the vessel-form member, wherein the vessel-form member and the flange portion are each formed of a rubber body including silicone rubber and a substrate fabric embedded in the rubber body, the substrate fabric including aramid short fibers or polyester fibers, and having a thickness of 0.25 mm or more. Accordingly, the inventive diaphragm does not only have durability during operation in both the high-temperature and the normal-temperature area but also exerts much better durability during operation in the low-temperature area.

Abstract: The vehicle brake-specific diaphragm of the invention includes a vessel-form member and a flange portion formed at a peripheral edge of an opening in the vessel-form member, wherein the vessel-form member and the flange portion are each formed of a rubber body including silicone rubber and a substrate fabric embedded in the rubber body, the substrate fabric including aramid short fibers or polyester fibers, and having a thickness of 0.25 mm or more.